This invention relates to a pre-processing system for use in pre-processing a fingerprint prior to identification of the fingerprint.
A fingerprint has uniquenss and unchangeability and therefore serves to identify each person in a criminal investigation. A recent attempt has been directed to application of identification of the fingerprint to a cash dispensing system and/or to a person identifying system of preventing an unauthorized person from entering an offlimits zone.
In such a cash dispensing system or the like, a fingerprint is impressed by a person on an input surface, namely, a finger positioning surface after a preliminary input of an identification code assigned to the person and is collated with a memorized fingerpeint pattern corresponding to the identification code. Thus, both of the fingerprint and the identification code are used in the cash dispensing system or the like to quickly identify each person.
In a copending U.S. patent application Ser. No. 755,810, filed July 17, 1985, by Ko Asai et al, the present applicants, it is pointed out that each fingerprint is preliminarily processed prior to identification of the fingerprint. Such preliminary processing is carried out so as to extract a distinct and clear fingerprint impression and to distinguish between a true fingerprint impression extracted from an actual fingertip of each person and a forged fingerprint impression willfully placed on the input surface.
Any other preliminary processing or pre-processing may preferably be carried out for each fingerprint to accurately identify each person and to reject the forged fingerprint impression. For example, it is preferable that each fingerprint is impressed on a center portion of the input surface. This is because a great deal of image signals can be extracted from the fingerprint and accurately collated with the memorized fingerprint pattern, when the fingerprint is impressed on the center portion.